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 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
 *
 * This code is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License version 2 only, as
 * published by the Free Software Foundation.  Oracle designates this
 * particular file as subject to the "Classpath" exception as provided
 * by Oracle in the LICENSE file that accompanied this code.
 *
 * This code is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
 * version 2 for more details (a copy is included in the LICENSE file that
 * accompanied this code).
 *
 * You should have received a copy of the GNU General Public License version
 * 2 along with this work; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
 *
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package jdk.graal.compiler.hotspot;

import jdk.graal.compiler.core.common.CompressEncoding;
import jdk.graal.compiler.debug.GraalError;
import jdk.graal.compiler.hotspot.nodes.HotSpotCompressionNode;
import org.graalvm.word.LocationIdentity;

import jdk.graal.compiler.core.common.memory.BarrierType;
import jdk.graal.compiler.core.common.type.AbstractObjectStamp;
import jdk.graal.compiler.core.common.type.Stamp;
import jdk.graal.compiler.hotspot.replacements.HotSpotReplacementsUtil;
import jdk.graal.compiler.nodes.ValueNode;
import jdk.graal.compiler.nodes.gc.shenandoah.ShenandoahBarrierSet;
import jdk.vm.ci.meta.JavaKind;
import jdk.vm.ci.meta.ResolvedJavaField;
import jdk.vm.ci.meta.ResolvedJavaType;

/**
 * Specialization of {@link ShenandoahBarrierSet} that adds support for read barriers on handle
 * locations and compressed references.
 */
public class HotSpotShenandoahBarrierSet extends ShenandoahBarrierSet {
    private final CompressEncoding oopEncoding;

    public HotSpotShenandoahBarrierSet(ResolvedJavaType objectArrayType, ResolvedJavaField referentField, GraalHotSpotVMConfig config) {
        super(objectArrayType, referentField);
        this.oopEncoding = config.getOopEncoding();
        this.useLoadRefBarrier = config.getFlag("ShenandoahLoadRefBarrier", Boolean.class);
        this.useSATBBarrier = config.getFlag("ShenandoahSATBBarrier", Boolean.class);
        this.useCASBarrier = config.getFlag("ShenandoahCASBarrier", Boolean.class);
        this.useCardBarrier = config.getFlag("ShenandoahCardBarrier", Boolean.class);
    }

    @Override
    protected BarrierType barrierForLocation(BarrierType currentBarrier, LocationIdentity location, JavaKind storageKind) {
        if (location instanceof HotSpotReplacementsUtil.OopHandleLocationIdentity) {
            return BarrierType.READ;
        }
        return super.barrierForLocation(currentBarrier, location, storageKind);
    }

    @Override
    public BarrierType readBarrierType(LocationIdentity location, ValueNode address, Stamp loadStamp) {
        if (location instanceof HotSpotReplacementsUtil.OopHandleLocationIdentity) {
            GraalError.guarantee(loadStamp instanceof AbstractObjectStamp, "expect object, got: %s", loadStamp);
            return BarrierType.READ;
        }
        return super.readBarrierType(location, address, loadStamp);
    }

    @Override
    public BarrierType writeBarrierType(LocationIdentity location) {
        if (location instanceof HotSpotReplacementsUtil.OopHandleLocationIdentity) {
            return BarrierType.FIELD;
        }
        return BarrierType.NONE;
    }

    @Override
    protected ValueNode maybeUncompressReference(ValueNode value, boolean narrow) {
        if (value != null && narrow) {
            return HotSpotCompressionNode.uncompressWithoutUnique(value.graph(), value, oopEncoding);
        }
        return value;
    }

    @Override
    protected ValueNode maybeCompressReference(ValueNode value, boolean narrow) {
        if (value != null && narrow) {
            return HotSpotCompressionNode.compressWithoutUnique(value.graph(), value, oopEncoding);
        }
        return value;
    }
}
